1. Field of the Invention
The present invention relates to a method for forming and denaturing particles. More particularly, the present invention relates to a method for forming and denaturing particles based on the utilization of a light-induced phase transition of a polymer solution, which permits the formation, modification and processing of polymer particulates and manufacture of switching devices and three-dimensional memories.
2. Description of Related Art
In various fields such as physics, chemistry, biochemistry and electronics, technologies have been studied for micro-processing, control of microstructures, and alteration, processing and modification of matters including biocells, inorganic and organic substances on the micron and submicron order, resulting in practically excellent techniques and structures.
Generation of particulates and control of the dynamic patterns thereof form an area among these new technologies and are attracting attention as an important source of innovations to be achieved hereafter.
The present inventors have carried out extensive studies to open up a new technological prospect, with their eyes on various phenomena regarding generation of particles and control thereof as described above. Phase transition in a polymer solution was one of the phenomena noted in the course of these research efforts. This phase transition is known as a phenomenon in which, when a poly (N-isopropylacrylamide) solution is kept at a temperature more than 31.degree. C., for example, phase transition takes place, leading to generation of particulates of polymer of the submicron order and non-uniform aggregates thereof: phase transition between solid and liquid phases.
However, because the phase transition phenomenon, known as an object of scientific interest, produced only submicron-order particulates and non-uniform aqgregates thereof, development thereof into practicable technologies has been limited.
Particle manipulation based on the utilization of phase transition has been impossible for the conventional technologies, and almost no efforts have so far been made to make such manipulation possible.
However, from the point of view that the solid-liquid phase transition suggested the possibility of generating and manipulating particulates, the present inventors have made their utmost efforts to develop a means to permit such generation and manipulation with a satisfactory reproducibility and high selectivity.